Rubber drum for ball mills pebble mills, and like machines



Feb.. 20, 1951 F. MCINTYRE 2,542,778

RUBBER DRUM FOR BALL MILLS, PEBBLE MILLS, AND LIKE MACHINES Filed Sept. 13, 1945 5 Sheets-Sheet l www , avec, M4 L MILLS, AND LIKE MACHINES 103029 .al .35 34 3130 J0 F. MCINTYRE RUBBER DRUM FOR BALL MILLS, PEBBLE lll Feb. 20, 1951 Filed Sept. 13, 1945 Feb. 20, 1951 F. MCINTYRE 2,542,778

RUBBER DRUM RoR BALL MILLS, PEBBLE MILLS, AND LIKE MACHINES Filed Sept. 13, 1945 3 Sheets-Sheet 3 lber lining to the 'consists basically of Patented Feb. 2o, 1951 RUBBER DRUM ron BALL MILLS, PEBBLE MILLS, AND Lum MACHINES Frank McIntyre, London,

England, assigner to Wilkinson Rubber Linatex Limited, London,

England Application September 13, 1945, Serial No.

In Great Britain October 20, 1944 Claims. (CL 241-66) Ball mills, pebble mills and like machines for use in grinding ores and ceramic and other materials have a rotary metal tumbler drum, and it has been proposed to line the drums of such machines with rubber for the purpose of protecting the same against abrasion by the contents of the drum and of preventing metallic contamination of the contents of the drum.

EiTective bonding and/or anchorage of the rubmetal drum has however been difficult to achieve because of the tremendous shearing forces to which the lining is subjected in use. Also difliiulties have arisen due to fatigue or breaking away of the rubber where it contacts with and is secured to the rigid metal surface.

The invention provides a rotary tumbler drum for a ball mill, pebble mill or like machine, comprising a tubular rubber bodygmounted in compression between end plates on a number of longitudinally extending rods which connect'the end plates and are enclosed within the rubber body. The drum according to the invention thus rubber, stlilened by the distinct from being conlined with rubber More. over the rubber, being held in compression, is better able to resist abrasion and cutting than is a rubber lining bonded to an existing metal drum.

The rods and end plates are preferably made of steel or other suitable metal, although nonmetallic materials could be used provided they are of adequate rigidity. The rods are preferably of circular section The rubber body is preferably built up of a number of rings threaded on to the rods.. Ihe rings may conveniently be held in compression on the rods by means oi nuts screwed on to threaded ends of the rods, The rings may be made of sinuous form, either at their external or at their internal periphery, the crests of the waved formation lying opposite the rods so that the effective thickness of the rubber is substantially equal throughout the periphery of the drum.

While a drum in which the body, apart from the rods, consists wholly of rubber is suitable for small sized mills, it is necessary for larger mills to employ drums in which the rubber rings are interleaved with metal rings which are also threaded on the rods and project externally beyond the rubber rings.- These metal rings serve as cooling nns to conduct heat away from the rubber. They also serve to stiien the drum against torsion and to support the rods against bending. The internal diameter of the metal rings is generally greater than that of the rub through-going rods, as stituted by a metal body 20 Some alternative form 2 ber rings. the inner edges of the metal rings being maintained out of contact with the contents lo1' the drum, for example, by reason of the rubber rings on either side shielding the metal by virtue of their compression.

The fins may be connected by a system of wires, rods, or bars running helically around the outer surface of the drum, external to the rubber and connected to the end plates, to provide a further bracing against torsion. Alternatively, or in addition, tapering metal plates extending longitudinally from and tapering in width from the end plate at the driven end of the drum to the other end plate and external to the `rubber and ilns may be used as a torsion bracing.

'I'he metal end plates will, in general. be provided with an internal lining of rubber bonded to the metal and held down by specialV burred washers.

of tumbler drums according to the invention will now be described in more detail with reference to the accompanying drawingsl in which,

Fig. 1 is a side elevation, partly in section of the first form,

Figs. 2 and 3 are respectively sections on lines II-II and III-III in Fig. 1,

Fig. 4 is a side elevation of the second form ot drum,

Figs. 5 and 6 are enlarged sectional views, similar to Fig. 4, showing alternative constructions of inspection cover, and Fig. 7 is a detail view looking in the direction of the arrow X in Fig. 6.

Like reference characters designate like parts throughout the ilgures.

Referring ilrst to Figs. 1-3, the body of the drum comprises a number of rubber rings ill threaded on to longitudinally extending and circumferentially spaced metal rods I I These rods have threaded ends I2 accommodated in holes in metal end plates I3, i 4, and nuts I5 screwed on to the threaded ends I2 of the rods maintain the rubber rings Il) in compression. Between consecutive rubber rings are located metal rings I6, which are also threaded on the rods Il and which extend beyond the outer periphery of the rubber rings to serve as cooling ns. The metal rings I6A are of larger internal diameter than the rubber rings i0, so their inner edges are shrouded and so maintained out of contact with the contents of the drum by reason of the compression of the rubber rings as shown in Fig. 1. As shown in Fig. 2, the rubber rings I0 are of sinuous form at their internal periphery, the crests i1 of their undulations lying opposite the rods Il vso that sesame the effective thickness oi the rubber rings is constant throughout their periphery.

The end plates I3, I4 carry respectively trunnions I8, I9 to be accommodated in bearings in the ball mill or the like and trunnion I8 serves to transmit the drive to the drum.

The metal plates I6 serve to stillen the drum against torsion and to support the rods I I against bending. Further torsion bracing is provided by wires 20 extending helically around the outer surface of the drum, the wires being attached at their ends to the end plates as indicated at 2I and passing through holes 22 (Fig. 2) in the pro jecting portions of the metal plates I6.

Each of the metal end plates I3, I4 is provided with an internal lining 23 of rubber bonded to the metal by a ply 24 of fabric, and also secured to the metal by buried washers, each of which is constituted by a metal plate 25 carrying a bolt 26 having a countersunk head 21, nuts 28 securing the bolts to the end plates.

A loading and inspection aperture is provided, this being defined by a rectangular angle iron framework 29 (Figs. 2 and 3). The rubber and metal rings are cutaway, as indicated, to accommodate this framework, and one of the rods III is interrupted, its ends II2 being threaded into opposite members of the framework 29. Welded to the framework are two bars 30, which are threaded over the interrupted rod III and over the two adjoining rods II as shown in Fig. l. The framework 29 carries an internal rubber lining 3I and four upstanding bolts 32. A cover for the aperture is provided, this being constituted by a metal plate 33, having holes to nt over the bolts 32 and carrying an internal rubber lining 34 consisting of three pads of rubber, the. uppermost of which is secured by a buried washer 35 and nut 36 to the metal plate. The cover is held down by nuts 31 fitted to the bolts 32 and two layers 38 of rubber mounted between the metal plate 33 and the upper rubber pad 34 bed down on to the top of the framework 29 to form a tight joint.

The drum shown in Fig. 4 is in every respect` similar to that of Figs. 1-3, except that the torsion bracing wires are replaced by tapering metal plates 39 external to the drum, which extend longitudinally and are fixed at their opposite ends to the end plates, the plates 39 tapering in wifi-1 from the end plate I3 at the driven end of the drum to the end plate I4 at the other end.

In Figs. 5 and 6 are shown alternative forms of inspection aperture. In both cases the aperture is circular and the cover is constituted by f.

a plug which can be introduced into position and removed by manipulation of a hand-wheel. The operation of removing or replacing the cover can thus be eifected more rapidly than in the case of Fig. 3, where four nuts 31 have to be dealt with.

Considering first of all Fig. 5, the inspection aperture is defined by a circular metal frame |29. to which are attached packing pieces 229 and into which the threaded ends II2 of the interrupted rod III are screwed. The frame I2!) is secured to the metal rings I6 nearest the aperture by screws 48 introduced into the packing pieces 229, and has an internal rubber lining 3I.

The cover comprises, as before, a metal plate 33 having an underlying layer 38 of rubber which, in this case, beds down on a rubber strip I3I bonded to the frame |29 and lining 3l. Beneath the rubber layer 38 is a wooden plug 4I shrouded in rubber 42 and two rubber discs 43, 44, all the constituent parts of the cover plug being bonded 75 together. Attached to the rubber disc 4B by a buried washer 45 is a bolt 48 held against rotation in relation to the plate 33 by a key 41 engaging in a keyway 46 in the plate. A handwheel 49 is fitted to the threaded end af the bolt 46. On screwing down the hand-wheel 49, the bolt 46 will lift in relation to the metal plate 33 and expand the rubber disc 43 into binding engagement with the framework 39.

The arrangement of Fig. 6 is generally similar. so far as the inspection aperture is concerned. Pins 56 projecting upwardly from the frame |23 engages in keyhole slots I5II (Fig. 7) in the metal top plate 33 of the cover plug, which, after engaging the enlarged parts I5I of the slots with the pins 50, requires turning by means of the bosses 5I to bring the pins out of register with said enlarged parts I5I.A Beneath the metal plate 33 and held thereto by rivets 52, are a metal compression plate 53 and a pair of rubber discs I43. A buried washer 45 supports an upstanding pin 54, and an inner layer |44 of rubber is bonded to the underside of the plug. The handwheel I49 has an externally threaded portion 55 engaging in a threaded boss 56 on the plate 33. When the hand-wheel I49 is screwed down the compression plate 53 is forced downwardly to expand the rubber discs |43 into binding engagement with the framework 129. It will be noticed that the rivets 52 pass with clearance through holes 51 in the compression plate, thus enabling the compression plate to move up or down in relation to the top plate 33.

Any desired type of rubber, either natural or synthetic, may be used in the construction of the drum according to the invention, but I prefer to employ, because of its especially high 'resistance to abrasion, the material manufactured by the process described in British Patent No. 437,- 928, i. e. by incorporating in latex a vulcanising ingredient, such as sulphur, and an accelerator, coagulating the mixture, separating the coagulum from the residual liquor, preparing crepe or sheet rubber from the coagulum, drying the rubber underconditions such that substantially no vulcanisation takes place, and thereafter effecting very slow vulcanisation of the dry rubber, the period of vulcanisation extending from one or two weeks to several months. Another form of rubber having ahigh degree of resistance to abrasion and particularly suitable for my purpose is that made by the process described in U. S. Patent No. 2,358,195.

Tumbler drums constructed in accordance with the invention are suitable for use in concrete mixing machines, in place of the usual metal drums. In this case, the rubber will not only act to resist abrasion but also to reduce the tendency of the material to cake. They are also capable of use where chemicals are present which corrode metal but do not attack rubber.

What I claim as my invention and desire to secure by Letters Patent is:

1. A' rotary tumbler drum, comprising a pair of end plates, a plurality of longitudinal rods extending between and connecting said end plates, and a tubular body portion comprising a plurality of rubber rings and metal stiffening rings disposed between certain adjacent rubber rings at least. said rubber and metal rings being threaded on said rods and held in compression between said end plates, and said metal rings projecting externally beyond said rubber rings to constitute cooling tins.

2. A drum as claimed in claim 1, in which the metal rings are oi' greater internal diameter than the rubber rings, their inner edges being shrouded by the compressed rubber rings.

3. A rotary tumbler drum, comprising a pair of end plates, a plurality of longitudinal rods extending between and connecting said end plates, a tubular body portion comprising a plurality of rubber rings and metal stiiening rings disposed between certain adjacent rubber rings at least, said rubber and metal rings being threaded on said rods and held incompression between said end plates, and said metal rings projecting externally beyond said rubber rings `'to constitute cooling iins, and torsion bracing members extending helically round the drum through holes in the projecting portions of the metal rings, said bracing members being connected to said end plates.

4. A rotary tumbler drum, comprising a pair of end plates, a plurality of longitudinal rods extending between and connecting said end plates. a tubular body portion comprising a plurality of rubber rings and metal stiiening rings disposed between certain adjacent rubber rings at least,

said rubber and metal, rings being threaded on said rods and held in compression between said end plates, and said metal rings projecting externally beyond said rubber rings to constitute cooling ilns, and torsion bracing plates extend@ ing longitudinally of the drum and connected to the end plates, said bracing plates tapering in width from one end of the drum to the other.

5. A drum as claimed in claim 1, having a loadlng and inspection aperture dened by a framework held mounted in the body of the drum, the metal and rubber rings being cutaway locally to accommodate said framework, and a removable cover plug to t in said framework.

6. A drum as claimed in claim 1, having a loading and inspection aperture defined by a framework held mounted in the body of the drum, the metal and rubber rings being cutaway locally to accommodate said framework, and a removable cover plug to fit in said framework, said cover plug comprising at least one rubber disc and a screw operable for expanding said rubber disc into binding engagement with said aperture-deilning framework.

7. A `rotary tumbler drum, comprising a pair 'l oi' end plates, a tubular rubber body held in axial compression throughout its entirety between said end plates, and a plurality of continuous longitudinal members embedded in said rubber body and connecting said end plates, said members serving to stiien said rubber body and to hold the same in axial compression.

8. A rotary tumbler drum, comprising aA pair of end plates, a tubular rubber body for retaining contained material within the drum, said body having an uninterrupted interior rubber surface and a plurality of longitudinal rods extending throughout its entirety between and connecting said end plates, said rubber body being mounted in axial compression between said end plates and said rods being enclosed within said rubber body and serving to stillen said body and to hold the same axially compressed.

9. A rotaryV tumbler drum, comprising a pair of end plates, a tubular rubber body and a plurality of longitudinal rods extending between.

and connecting said end plates, said body being,

constituted by a plurality of rubber rings, which abut against one another to provide a continuous rubber surface 'throughout the whole interior of the body, which are threaded on said rods and which are held in compression between said end plates.

10. A rotary tumbler drum, comprising a pair of end plates, a plurality of longitudinal rods extending between and connecting said end plates, a. tubular body portion comprising a plurality of rubber ringsv and metal stiffening rings' disposed between certain adjacent rubber rings at least, said rubber and metal rings being threaded on said rods and held in compression between said end plates, and said metal ringsA projecting externally beyond said rubber rings to constitute cooling fins, and bracing members external to the body portion and connecting the end plates.

FRANK MCINTYRE. REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name `Date i 536,112 Western Mar. 19, 1895 673,768 Fleming May 7, 1901 1,238,652 Ensign Aug. 28, 1917 1,249,764 Johnson Dec. 11, 1917 1,601,956 Gammeter Oct. 5, 1926 1,607,828 Holthofi 1 Nov. 23, 1926 1,907,785 Garlick May 9, 1933 1,921,672 Haushalter Aug. 8, 1933, 2,122,399 Abbe July `5, 1938 OTHER REFERENCES Engineering and Mining Journal, Press, Sep tember 1924, vol. No. 12, page 476, McGraw- Hill Co. Inc., 10th Avenue at 36th Street, New York city. 

